A wildfire that roared with little warning into a Northern California city claimed two lives as thousands of people scrambled to escape before the walls of flames descended from forested hills onto their neighborhoods, officials said Friday.

"I've never experienced something so terrifying in my life," said Liz Williams, who loaded up two kids in her car and then found herself locked in bumper-to-bumper traffic with neighbors trying to retreat from Lake Redding Estates. She eventually jumped the curb onto the sidewalk and "booked it."

"I didn't know if the fire was just going to jump out behind a bush and grab me and suck me in," Williams said. "I wanted out of here."

The blaze leveled dozens of homes, leaving neighborhoods smoldering and 37,000 people under evacuation orders.

AP

Flames engulf a historic schoolhouse Thursday in Shasta, California.

The flames moved so fast that firefighters working in oven-like temperatures and bone-dry conditions had to drop efforts to battle the blaze to help people escape.

The fire, which created at least two flaming tornados that toppled trees, shook trucks and shattered windows, took "down everything in its path," said Scott McLean, a spokesman for Cal Fire, the state agency responsible for fighting wildfires.

Fire officials warned that the blaze would probably burn deeper into urban areas before there was any hope of containing it, though it either changed direction or was stopped before it could burn into the core of the city.

The fire was likely to regain strength later in the day when temperatures were forecast to spike around 110 degrees and winds were expected to kick up.

Redding sits at the northern end of the agricultural Central Valley, surrounded by a scenic landscape. Rivers channel abundant winter rainfall into massive reservoirs used for boating and fishing. The area's stunning mountains, including snow-capped Mount Shasta, topping 14,000 feet, are a playground for outdoor enthusiasts.

Lightning and even a lawn mower have sparked devastating fires in the forests that ring the peaks and lakes. The blaze that broke out Monday was caused by a mechanical issue involving a vehicle, officials said.

The fire rapidly expanded Thursday when erratic flames swept through the historic Gold Rush town of Shasta and nearby Keswick, then cast the Sacramento River in an orange glow as they jumped the banks into Redding.

Steve Hobson, a former firefighter, said flames on the distant hillside looked like solar flares on the sun.

He had planned to stay behind to save his house on Lake Redding Drive. But the heat burned his skin, and smoke made it hard to breathe. He could feel the fire sucking the air from around him, whipping up swirling embers in a "fire tornado," he said.

He had to drive through walls of flaming embers on both sides of the street when he finally fled. A tree fell right in front of him.

"I didn't know if I'd make it so I just got in the middle of the street, went down the middle of the street through the embers and the smoke and made it past," Hobson said.

When he returned Friday, his fence had burned along with a backyard shed and everything inside it - Christmas ornaments, china and old televisions. But his house made it through the harrowing night.

At least 66 homes were destroyed in Hobson's neighborhood, according to an Associated Press survey of damage. Aerial footage showed dozens of homes in ruins in Keswick Lake Estates. Some 5,000 other buildings were threatened, fire officials said.

A firefighter with the Redding Fire Department was killed in Shasta County. Another firefighter hired to try to contain the flames with a bulldozer was killed Thursday, authorities said.

Fire crews in Redding for a time abandoned any hope of containing the flames and instead focused on saving lives.

"We're not fighting a fire," said Jonathan Cox, battalion chief with Cal Fire. "We're trying to move people out of the path of it because it is now deadly, and it is now moving at speeds and in ways we have not seen before in this area."

Late Thursday, crews found the body of the bulldozer operator who had been hired privately to clear vegetation in the blaze's path. He was the second bulldozer operator killed in a California blaze in less than two weeks.